DOE OSTI2020
La2Fe(SeO)2 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are four inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a 4-coordinate geometry to four Se2- and four O2- atoms. There are a spread of La–Se bond distances ranging from 3.22–3.53 Å. There are a spread of La–O bond distances ranging from 2.38–2.48 Å. In the second La3+ site, La3+ is bonded in a 4-coordinate geometry to four Se2- and four O2- atoms. There are a spread of La–Se bond distances ranging from 3.22–3.48 Å. There are a spread of La–O bond distances ranging from 2.39–2.45 Å. In the third La3+ site, La3+ is bonded in a 3-coordinate geometry to five Se2- and three O2- atoms. There are a spread of La–Se bond distances ranging from 3.10–3.46 Å. There are one shorter (2.35 Å) and two longer (2.40 Å) La–O bond lengths. In the fourth La3+ site, La3+ is bonded in a 3-coordinate geometry to five Se2- and three O2- atoms. There are a spread of La–Se bond distances ranging from 3.14–3.33 Å. There are a spread of La–O bond distances ranging from 2.33–2.40 Å. There are two inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded in a distorted linear geometry to four Se2- and two O2- atoms. There are a spread of Fe–Se bond distances ranging from 2.87–2.96 Å. There is one shorter (1.97 Å) and one longer (1.98 Å) Fe–O bond length. In the second Fe2+ site, Fe2+ is bonded to four Se2- atoms to form corner-sharing FeSe4 tetrahedra. There are a spread of Fe–Se bond distances ranging from 2.53–2.62 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to six La3+ atoms. In the second Se2- site, Se2- is bonded in a 6-coordinate geometry to two La3+ and four Fe2+ atoms. In the third Se2- site, Se2- is bonded in a 1-coordinate geometry to four La3+ and three Fe2+ atoms. In the fourth Se2- site, Se2- is bonded in a 1-coordinate geometry to six La3+ and one Fe2+ atom. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to three La3+ and one Fe2+ atom to form OLa3Fe tetrahedra that share corners with four OLa3Fe tetrahedra and edges with two equivalent OLa4 tetrahedra. In the second O2- site, O2- is bonded to three La3+ and one Fe2+ atom to form OLa3Fe tetrahedra that share corners with four OLa3Fe tetrahedra and edges with two equivalent OLa4 tetrahedra. In the third O2- site, O2- is bonded to four La3+ atoms to form a mixture of corner and edge-sharing OLa4 tetrahedra. In the fourth O2- site, O2- is bonded to four La3+ atoms to form a mixture of corner and edge-sharing OLa4 tetrahedra.